1. Field of the Invention
The present invention relates to an image processing apparatus and method of controlling the same. More particularly, the invention relates to an image processing apparatus and method of controlling the same in which it is possible to resume a job that has been suspended during execution.
2. Description of the Related Art
If supply of power to an image processing apparatus is cut off unexpectedly during execution of a job and the job is suspended as a result, it is preferable that resumed execution of the suspended job be possible the next time supply of power is restored. The specification of Japanese Patent Laid-Open No. 2000-181735 discloses a technique in which information indicating the progress of a job is stored in a non-volatile storage unit when the job is executed, and the job is resumed automatically based on the progress information read out of the storage unit upon resumption of the job.
In an embedded device such as a copier or printer, it is required that the time needed to respond to a request fall within fixed limits. In order to achieve this, an embedded real-time operating system (referred to as a “real-time OS” below) that emphasizes a real-time feature is used. With a conventional real-time OS, it is required that enough memory capacity for all applications that run at one time be reserved in physical memory. Consequently, the storage capacity of installed physical memory is continuing to increase as more functions are added to recent embedded devices.
In the prior art, however, the procedure followed to start up an apparatus is fixed regardless of whether a suspended job is waiting when power is re-introduced. Accordingly, in a case where a job has been suspended owing to cut-off of power, etc., all software modules including those unrelated to the suspended job are loaded in a prescribed sequence until the job is resumed. As a consequence, the length of time from re-introduction of power to resumption of the job is too long and the execution of new jobs is delayed. The result is a decline in productivity.